title: Dietary patterns and breast cancer risk in the California Teachers Study cohort.
abstract: BACKGROUND
  Evidence that diet is associated with breast cancer risk is inconsistent. Most studies have examined risks associated with specific foods and nutrients, rather than measures of overall diet.
  
  
  OBJECTIVE
  This study aimed to evaluate dietary patterns and their relation to breast cancer risk in a large cohort of women.
  
  
  METHODS
  Data from 91,779 women in the California Teachers Study cohort were analyzed, including data from 4140 women with a diagnosis of invasive breast cancer made between 1995 and 2009. Five predominant dietary patterns were identified by using principal components factor analysis: a plant-based diet, high in fruit and vegetables; a high-protein, high-fat diet, high in meats, eggs, fried foods, and high-fat condiments; a high-carbohydrate diet, high in convenience foods, pasta, and bread products; an ethnic diet, high in legumes, soy-based foods, rice, and dark-green leafy vegetables; and a salad and wine diet, high in lettuce, fish, wine, low-fat salad dressing, and coffee and tea.
  
  
  RESULTS
  The plant-based pattern was associated with a reduction in breast cancer risk (RR: 0.85; 95% CI: 0.76, 0.95 for the highest compared with the lowest consumption quintile; P-trend = 0.003); risk reduction was greater for estrogen receptor-negative progesterone receptor-negative (ER-PR-) tumors (RR: 0.66; 95% CI: 0.48, 0.91; P-trend = 0.03). The salad and wine pattern was associated with an increased risk of estrogen receptor-positive progesterone receptor-positive tumors (RR: 1.29; 95% CI: 1.12, 1.49); this effect was only slightly attenuated after adjustment for alcohol consumption.
  
  
  CONCLUSIONS
  The finding that greater consumption of a plant-based dietary pattern is associated with a reduced breast cancer risk, particularly for ER-PR- tumors, offers a potential avenue for prevention.
authors.affiliation: From Cancer Epidemiology, Mailman School of Public Health, Columbia University, New York, NY (LBL); the Cancer Prevention Institute of California, Fremont, CA (AJC, CAC, and PLH-R); the Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA (CAC and PLH-R); the Division of Cancer Etiology, Department of Population Sciences, Beckman Research Institute, City of Hope, Duarte, CA (LB); the Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA (DOS and GU); the Cancer Registry of Norway, Oslo, Norway (GU); and the Department of Nutrition, University of Oslo, Oslo, Norway (GU).
authors.forename: Lilli B
authors.initials: LB
authors.lastname: Link
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Canchola
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
authors.forename: Christina A
authors.initials: CA
authors.lastname: Clarke
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Stram
authors.forename: Giske
authors.initials: G
authors.lastname: Ursin
authors.forename: Pamela L
authors.initials: PL
authors.lastname: Horn-Ross
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D004032:Diet / Q000009:adverse effects; D014676:Diet, Vegetarian; D002523:Edible Grain; D005178:Faculty; D005260:Female; D005638:Fruit; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism; D025341:Principal Component Analysis; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014675:Vegetables
chemical_list: D009363:Neoplasm Proteins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone